1. Field of the Invention
The present invention relates to a light source device and a control method of the light source device.
2. Description of the Related Art
A light source device for illumination device of an endoscope is disclosed in, for example, International Publication No. 2013/150897. In this light source device, a red LED, a green LED and a blue LED are used as light sources. This light source device combines the light emitted from these LEDs to emit white light as illumination light. The light source device is provided with an optical sensor that detects a quantity of the light emitted from each LED. On the basis of the light quantity detected by the optical sensor, the light source device adjusts emission intensity of each LED and regulates a color of the illumination light into appropriate white. However, in International Publication No. 2013/150897, it is not specifically disclosed how to detect the light quantity of each LED.
For example, in an endoscope system, there is a width of several thousand times between a maximum light quantity and a minimum light quantity of the illumination light. Furthermore, for example, for the purpose of adjusting a color balance, it is necessary to adjust the light quantity of each color at a level of several %. Consequently, as a detection range of the optical sensor, there is required a wide range in which a maximum value is tens of thousands times as large as a minimum value. However, a usual optical sensor does not have such a wide detection range.